Galactooligosaccharide supplementation reduces stress-induced gastrointestinal dysfunction and days of cold or flu: a randomized, double-blind, controlled trial in healthy university students.

BACKGROUND: Acute psychological stress induced by academic exams is associated with dysregulated gastrointestinal and immune function.

OBJECTIVE: We examined whether supplementation with galactooligosaccharides reduced gastrointestinal dysfunction and the percentage of days with cold or flu in academically stressed undergraduate students.

DESIGN: In a randomized, double-blind study, subjects (n = 427) received 0, 2.5, or 5.0 g galactooligosaccharides for 8 wk around the time of fall final exams. Levels of stress and cold or flu symptom intensity (SI; 0 = not experiencing to 3 = severe) were recorded daily. The SI from 9 cold or flu symptoms was summed with 1 d of cold or flu defined as a sum >6. The Gastrointestinal Symptom Response Scale was completed weekly.

RESULTS: Stress was positively related to diarrhea, indigestion, and reflux syndromes and with abdominal pain, average daily cold or flu SI score, and the percentage of days with cold or flu. Gastrointestinal symptom scores for diarrhea (P = 0.0298), constipation (P = 0.0342), abdominal pain (P = 0.0058), and indigestion (P = 0.0003) syndromes were lower after galactooligosaccharide supplementation. The cold or flu SI score was affected by galactooligosaccharides and stress (P < 0.0001); 2.5 g was associated with a lower SI score across all levels of stress, but 5.0 g was protective only at lower levels of stress. The percentage of days with cold or flu was associated with galactooligosaccharides within different body mass index categories (P = 0.0002), wherein a 40% reduction in the percentage of days with cold or flu was observed in normal-weight individuals with 5.0 g galactooligosaccharides. This effect was not observed in overweight or obese individuals.

CONCLUSIONS: Acute psychological stress was directly related to symptoms of gastrointestinal dysfunction and cold or flu. Galactooligosaccharide supplementation reduced these symptoms and the number of days with cold or flu. This trial was registered at as NCT01137760.




デザイン:無作為化二重盲検試験において、被験者(n=427)は、秋期末試験ごろに、0、2.5、または5.0gのガラクトオリゴ糖を8週間摂取した。ストレスレベル及び風邪またはインフルエンザの症状強度(SI; 0=経験していない、3=重度)を毎日記録した。風邪またはインフルエンザの9症状のSIを、合計> 6として定義される風邪またはインフルエンザの1 日と加算した。胃腸症状レスポンス尺度(Gastrointestinal Symptom Response Scale)を毎週記入した。

結果:ストレスは、下痢、消化不良、及び逆流症候群、ならびに腹痛、風邪またはインフルエンザの平均一日SIスコア、及び風邪またはインフルエンザの日数の割合と正に関連した。各症候群におけるガラクトオリゴ糖の補給後の消化器症状スコアは、下痢(P=0.0298)、便秘(P=0.0342)、腹痛(P=0.0058)、および消化不良(P=0.0003)で低下した。風邪またはインフルエンザのSIスコアは、ガラクトオリゴ糖とストレスの影響を受けた(P < 0.0001)。すなわち、2.5 gは全てのストレスレベルにわたって低いSIスコアに伴っていたが、5.0 gは低ストレスレベルでのみ保護的であった。風邪またはインフルエンザの日数の割合は、異なる体格指数のカテゴリでガラクトオリゴ糖と関連し(P=0.0002)、5.0 gのガラクトオリゴ糖で正常体重個体において、風邪またはインフルエンザの日数の割合の40%減少が観察された。この効果は、過体重または肥満の個体では認められなかった。